Premature Thelarche and Adrenarche

Definitions

Puberty is the developmental stage during which secondary sexual characteristics appear.

Precocious puberty is the onset of puberty at an abnormally early age; usually before the age of 8 in girls and 9 in boys. This number may be lower for African American or Hispanic patients.

Thelarche is the onset of female breast development.

Pubarche is the appearance of sexual hair.

Adrenarche is the onset of androgen-dependent body changes such as growth of axillary and pubic hair, body odor, and acne.

Menarche is the onset of menstruation.

Normal Puberty

Normal puberty begins between ages 8-12 years in girls and 9-14 years in boys.

Tanner stage 2 breast development in girls

Tanner stage 2 testicular enlargement in boys

From a physiologic standpoint, this results when pulsatile secretion of GnRH begins and the hypothalamo-pituitary-gonadal axis is activated.

Criteria for defining the stages of puberty, proposed by Marshall and Tanner in 1969 and 1970, remain the standard of practice.

Premature Adrenarche

Premature adrenarche is the appearance of sexual hair (e.g., pubic, axillary) without other signs of sexual development. In the literature, the age ranges for diagnosis differ, but general practice dictates that the diagnosis be considered if signs develop in girls < 8 years old and boys < 9 years old.

The appearance of pubic hair does not necessarily mean that true puberty has started.

Pathophysiology: GnRH secretion is activated early, either because of tumor (central or peripheral), but more commonly due to unexplained causes. This HPA axis dysfunction leads to DHEA and DHEA-S secretion from the adrenal glands that occurs earlier as well. The levels are normal for pubertal stage but elevated for chronologic age. The zona reticularis of the adrenals is responsible for androgen secretion.